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A broadband balun structure is developed through a hybrid combination of substrate integrated waveguide (SIW) and antipodal fin-line topologies. The signal at the balanced port is divided between two unbalanced ports using a broadband SIW power divider which is capable of an equal power division with low phase and amplitude imbalance over a wide bandwidth. The 180° phase difference is made by the...
A very small footprint rectifier designed to support the micro-robotic applications is proposed and presented in this paper. The frequency of 94GHz has been selected as the best tradeoff between receiving antenna size and available transmitter power. To comply with the swarm micro-robotic requirements in which every part should be mass-producible and little sensitive to fabrication tolerance, a wideband...
This paper explores, for the first time, the use of high responsivity heterostructure backward tunnel diodes to enhance the conversion efficiency of ambient microwave power harvesters. Progress in advancing the performance of low power rectifiers has been slowed because the maximum possible efficiency using Schottky diodes has been reached. Measurements of RF-to-DC conversion efficiency at −40dBm/2...
This paper presents the use of equivalent parametric circuit models for the investigation of fabrication tolerance sensitivity in substrate integrated waveguide (SIW) components. As the adopted models are parametric, they permit to easily determine the effect of small variations in the geometry of the component, due to the manufacturing process. This feature allows an extremely fast sensitivity analysis...
Millimeter wave identification (MMID) enables new improvement, such as the high number of different codes that can be ‘written’ on a tag, location sensing through narrow-beam antennas etc. In this paper novel compact chipless MMID tag is presented. The tag consists of a slot etched on the top of circular Substrate Integrated Waveguide (SIW) cavity. Reader concept based on frequency domain measurement...
Emerging millimeter-wave frequency applications require high performance, low-cost and compact devices and circuits. This is the reason why the Substrate Integrated Waveguide (SIW) technology, which combines some advantages of planar circuits and metallic waveguides, has focused a lot of attention in recent years. However, not all three-dimensional metallic waveguide devices and circuit are integrable...
A variable phase shifter based on substrate integrated waveguide (SIW) and liquid crystal (LC) is proposed and demonstrated in 57–65GHz. The permittivity of nematic LCs can be made variable by applying various intensities of electric or magnetic fields. By partially replacing the dielectric substrate of SIW with standard LC (E7) and embedding an electric bias structure, an electronically tunable phase...
This paper analyses the main configuration of the substrate integrated waveguide (SIW) allowing spatial arrangement and miniaturization. With the increasing performance demand on wireless systems, high-density millimeter-wave system integration techniques have been under intense development. The performance of the guided-wave structure is crucial for the design of millimeter and sub-millimeter systems...
A new bio-radar based on a harmonic six-port junction is proposed to improve the performances of monitoring vital sign systems. The amplitude of heart beat compared to the higher harmonics of breathing and the intermodulation product are the main factors influencing the accuracy of the detection. Simulation-based performance demonstrate the advantage of the novel method using the harmonic six-port...
In this paper, air-filled Substrate Integrated Waveguide (SIW) is proposed and demonstrated for the first time at U-band. This low-loss transmission line is developed on a low-cost multilayer Printed Circuit Board (PCB) process. The top and bottom layers may make use of an extremely low-cost standard substrate such as FR-4 on which base-band or digital circuits can be designed so to obtain a very...
In this paper, a 40 GHz zero-IF self-oscillating mixer (SOM) with low-power consumption, is proposed and demonstrated for the next generation of battery-free yet active mm-wave identification (MMID) tag. It exploits the mixing property of LC cross-coupled VCO, and by injection-locking the SOM to the reader's carrier frequency, it enables a direct-conversion to the baseband. It, therefore, does not...
This paper studies the problem of automatic detection of false rumors on Sina Weibo, the popular Chinese microblogging social network. Traditional feature-based approaches extract features from the false rumor message, its author, as well as the statistics of its responses to form a flat feature vector. This ignores the propagation structure of the messages and has not achieved very good results....
A type of frequency selective surface (FSS) using array of single-layer antenna-filter-antenna (AFA) elements is presented in this paper. The periodic element of the proposed FSS is built up by a square substrate integrated waveguide (SIW) cavity resonator with two stepped-impedance resonators (SIRs) orthogonally etched on the its front and back sides. Coupling scheme of the proposed FSS element has...
In this paper, a wideband substrate integrated waveguide (SIW) cavity backed patch antenna element is proposed for high-gain arrays at millimeter-wave bands. By compensating the inductance of the feeding metallic via with a capacitive ring slot on the ground plate, an additional resonance is introduced to the patch mode to expand the bandwidth. To suppress the backward radiation from the slot and...
Terrestrial applications of microwave power transmission (MPT) such as RFID is highly challenging. As the distance between energy transmitter and receiving circuit increases, the available received power ramps down, thus causing an abrupt drop in RF/DC conversion circuit. Numerous works have been reported recently, but resulting in very incremental improvements over the state of the art.
The joint operation of radar sensing and wireless communication, namely RadCom system, yields a unique platform to meet the requirements of future intelligent transportation networks. Taking advantages of OFDM waveform, the range-Doppler coupling issues can be overcome for radar applications and complex equalization filter is no longer necessarily used to cope with frequency-selective fading channel...
Anomaly detection in streaming data is of high interest in numerous application domains. In this paper, we propose a novel one-class semi-supervised algorithm to detect anomalies in streaming data. Underlying the algorithm is a fast and accurate density estimator implemented by multiple fully randomized space trees (RS-Trees), named RS-Forest. The piecewise constant density estimate of each RS-tree...
Finite element 2-D analysis was implemented to simulate the dielectric spectra of nanodielectrics. As a test case, silica modified with a high graft density of short molecules and a low graft density of epoxy compatible chains were incorporated into epoxy. TEM images of the composites filler distribution were used to construct the model geometry with the interfacial area specifically included. The...
Partial discharge (PD) is one of the major reasons for the insulation deterioration of the cable terminations. To avoid the rapid deterioration of the insulation caused by PD in air gap defects, a new method by filling nano-TiO2 particles in air gap defects to suppress the PD of the cable terminations. The typical defects are designed and the cable accessories accelerated aging and testing system...
This paper presents a 60 GHz low loss phase shifter characterized by 360 degree phase shift and low variation of insertion loss using GaAs pHEMT process. The circuit contains a reflection type phase shifter (RTPS) and a switch line type phase shifter (SLTPS). A pair of Schottky diodes connected by a length of microstrip line is terminated to the through and coupled ports of Lange coupler as reflective...
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